<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>

<body>
    <script>
        //声明形式
        class Person {
            constructor() {}

            speak() {}
        }

        //表达式形式
        const Person = class {
            constructor()
        }
    </script>
</body>

</html>